Is gestational diabetes related to breast cancer: a case-control study

The most common cancer known worldwide that causes widespread mortality of women is breast cancer. One of the less known risk factors in women is hyperinsulinemia. Since identifying the risk factors help primary prevention and early detection of breast cancer, this study was performed aimed to determine the relationship between gestational diabetes and breast cancer in women referred to the hospitals of Tehran Shahid Beheshti University of Medical Sciences.

This comparative study was conducted on 450 women (n=150 in case group, n=300 in control group) referring to the hospitals of Tehran Shahid Beheshti University of Medical Sciences. Case group consisted of women with breast cancer based on pathologic record and physician diagnosis that at least one year has passed from their disease and control group were women without breast cancer who referred to other clinics in the same centers. Women were collected through interview and completing the questionnaire. Data were analyzed by SPSS software (version 24) and Independent t-test, Chi-square, chance ratio and logistic regression. P<0.05 was considered statistically significant.

In case group, 30 (20%) and control group 17 (5.7%) had history of gestational diabetes. There was significant relationship between breast cancer and gestational diabetes (OR=3.64, CI= 95%, P<0.001,1.78-7.43), body mass index(OR=1.11,CI= 95%, P<0.001, 1.04-1.18) and age (OR=1.13, CI= 95%, P<0.001, 1.09-1.16). In women with a history of gestational diabetes, the risk of breast cancer was 3.64 times higher than the other of women (P<0.05).

Gestational diabetes can be regarded as a risk factor for breast cancer. It is suggested that gestational diabetes be used as an early indicator in the detection of breast cancer.